Talk:Crystal

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I don't care if YOU, PERSONALLY, think they read like a cut-and-paste job, they aren't. --corvus13

I thought so too, and you should care. Our goal here is to create a good encyclopedia, not to coddle your sensitivities. If an article by anyone looks copyrighted, it's everyone's responsibility here to say so, and it's the author's responsibility to clear it up. It's not about personalities--it's about content. You've cleared up that this stuff is written by you, and that's good. So the copyright issue is settled; no problem. Now there's the issue of exactly what culture this "folklore" is from. That needs to be spelled out here too. We're not singling you out for criticism here--everyone criticizes everyone else here, from PhD's to dropouts. That's the process, and it works pretty well. --LDC

Amorphous solids can be considered liquids that flow but very slowly

Yes and no. The stories about the old glass windows being thicker at the bottom than at the top are probably either not true or are misinterpreted (if you have a sheet of glass that's thicker on one end, you'd install it with the thick end down, wouldn't you?)

But here's the thing...any solid, amorphous or crystalline, that is kept under a sustained stress, is going to flow "very slowly". The reason for this is that any material has an equlibrium vacancy concentration, and vacancy diffusion under an applied stress will cause creep. In fact, this is true even at absolute zero, because of the zero-point energy. Sure, it might take trillions of years, but the equations predict it.

There are two fundamental differences between a liquid and a solid. One is that the constituents of a liquid have a rotational mode of motion. The other is the enthalpy change when a liquid solidifies. I know you don't get the enthalpy release in a glass transition. Any statistical mechanics guys out there know of any evidence that a glass has rotational modes? --MaterialsScientist

This has nothing to do with how the glass is installed in the window. Rather, it has to do with window glass that has been in situ for a long time (I'm not talking on the order of fifty years, either; more on the order of the six- and seven-hundred-year-old glass one finds in old British castles and churches; but definitely not the "trillions of years" referred to above). The glass is slightly thicker at the bottom in such windows, indicating a (very slow) flow downwards. Also, some glass bottles of Roman era have been found which have been squashed rather than broken. Glass is simply an extremely slow-flowing fluid.
Here at the University of Queensland, there is a physics experiment that has been taking place for some 80 years, involving a container of pitch. This so-called pitch drop experiment demonstrates this phenomenon of "liquid solids"; the container of pitch has a small hole in the bottom of it which allows the pitch to drip through it. In the 80 years the experiment has been running, I believe the pitch has dripped just seven times.thefamouseccles 01:40 13 Jan 2004 (UTC)


Not sure about the description of liquid crystals -- can anyone verify ? I was under the impression that a liquid crystal was a material which undergoes an ordering transition upon the application of an electrical field -- i.e. switches between crystal and amorphous easily with a external stimulus. -- Olof

Contents

[edit] Proposed merger

Oppose Crystal is a major topic in chemistry & geology, deserving a good article on structure, lattice types & lattice energies, geological aspects ("grain" etc), crystals in popular culture/jewellery, liquid crystals, etc. There should be a short section on crystallography that says, "Main article: Crystallography". Likewise, there should be a section called "Formation of crystals" which should say, "Main article: Crystallisation". Crystallisation is a very interesting and important process in itself, worthy of a full-length article. You can talk about how it occurs, trapping of impurities, seeding, how to grow crystals, supersaturation, etc. You could probably write two separate FACs with very little overlap of content. Walkerma 17:13, 3 March 2006 (UTC)

Oppose I agree Wowlookitsjoe 02:17, 22 March 2006 (UTC)

No merge - Walkerma said it all - Vsmith 03:04, 22 March 2006 (UTC)

Oppose - Totally agree with Walkerma.

Same here, I agree with him too.11:08, 5 April 2006 (UTC)
Oppose - I am preparing a revision of Crystallization, and it has little to do with Crystal: it will be rather a chemical engineer's POV. UbUb 15:31, 11 April 2006 (UTC)
and BTW, I am considering that POV - there is a third article to write, that of Crystallization (physics) which is not the garden I plow. UbUb

[edit] Add Smithsonian Education link?

Hello! I am a writer for the Smithsonian's Center for Education, which publishes Smithsonian in Your Classroom, a magazine for teachers. An online version of an issue titled "Minerals, Crystals, and Gems: Stepping Stones to Inquiry" is available at this address:

http://www.smithsonianeducation.org/educators/lesson_plans/minerals/index.html

If you think the audience would find this valuable, I wish to invite you to include it as an external link. We would be most grateful.

Thank you so much for your attention.

[edit] Out of Fashion?

"Inspired by the growing numbers and varieties of quasiperiodic crystals, the International Union of Crystallography has redefined the term crystal to mean ``any solid having an essentially discrete diffraction diagram, thereby shifting the essential attribute of crystallinity from position space to Fourier space. Within the family of crystals one distinguishes between periodic crystals, which are periodic on the atomic scale, and aperiodic crystals which are not. This broader definition reflects our current understanding that microscopic periodicity is a sufficient but not a necessary condition for crystallinity."

[edit] New sub-category needed

A new reference about crystal should also include the word as slang for methamphetamine.


[edit] Need Authorization

My website provides information about Crystals, How to Care for Crystals, and Metaphysical Properties of Crystals with an A to Z Guide of Crystals. There was some question as to whether my website is considered Spam, or whether it would be admissible. Please review my site and let me know whether I can add my link to the 'links' section of the Crystal Page. My intentions are only to provide additional information about the subject of Crystals for those that are interested. Thank you for your consideration, Marin My Link: http://www.reikiessentials.com/crystals.html —Preceding unsigned comment added by ReikiEssentials (talk • contribs)

[edit] Crystals & Mythology

Not to beat a dead horse...but the last line in this Wiki Page is: 'Crystals also figure or figured prominently as healing tools in a number of mythologies [1].'

By clicking on the '[1]' link you are taken to a Mythology website. I guess I don't see the different between my site www.ReikiEssentials/crystals.html and that person's site...aside from the fact that my site offers tons more information on crystals. Why is it that my link keeps being knocked off - when there is a similar link *with less info than I provide* on this page...Please advise. —Preceding unsigned comment added by ReikiEssentials (talk • contribs)

The above two messages were posted by a user who is promoting a commercial website. WP:Spam applies, and the link will be reverted and the user blocked if he/she continues. Vsmith 22:15, 14 September 2006 (UTC)

Hi Vicky, You blocked me so I thought I'd leave a message here. Thank you for your suggestion -- the Crystal Power. I guess I'm wondering if you can explain to me -- I saw the links on this page. The first one takes you to a site about a book. Isn't that considered Spam because as you assume with me, can we assume that the intention of the author of that link is to sell his book? The second link is similar in that you can buy the book or subscribe to the site for more information. How is a link ever not considered spam? Is it not spam if an outsider not related to a site adds it to a category?

I guess I'm wondering - if the information is not on WIKI, why is it considered Spam to add a legitimate link that offers more info on a subject than is posted on WIKI? Thanks, Marin —Preceding unsigned comment added by ReikiEssentials (talk • contribs) 14:05, 15 September 2006

Don't know who Vicky is, but... Yes, you will find existing links to sites that are likely spam links - some of which have been in place for a while, as I find 'em I remove 'em - but there's only one of me.
Re: the links referred to above, the first is to another wiki site (references a book, doesn't seem to be promoting it) - the second is to a most informative page on a commercial site. The second, if added by the site owners or someone connected could well have been spam - dunno w/out doing an exstensive history search.
If the info is not on wiki, then write the article or add content to an existing article based on reliable sourced information (not your own site per WP:OR problems). Simply adding external links to info is not what we're about. Writing an encyclopedia is the mission.
Vsmith 14:40, 16 September 2006 (UTC)

Wikipedia should really add more information on what a crystal is catagorized as that way stsudents could get more valuable research. Kittycat 02:17, 4 May 2007 (UTC)Dogwhisper_vet

[edit] Reference to Charmstone and New Age

I added these references not because I believe in crystals but because the word "crystals" is used often by people conversationally (and also is referenced in various Wikipedia articles) to refer to the belief system itself. I would suggest leaving it because the word 'crystals' has these 2 meanings and even though this is a scientific article, you can't just remove the meaning from the word. Thanks, laurap414 23:57, 7 August 2007 (UTC)

This is all covered in the Charmstone article, or if it's not, it can be added there, and there's a disambig page already to direct the reader to that usage of crystal, so I reverted your edits as being inappropriate for this particular article on crystals. KP Botany 00:07, 8 August 2007 (UTC)
Alright but the disambig is only there because I added it. I have gone into several articles referencing crystals and changed the reference to crystals to avoid confusion. Thanks, laurap414 00:26, 8 August 2007 (UTC)
Oh, good, crystal is used for too much to not have a disambig on this page, thanks. KP Botany 00:39, 8 August 2007 (UTC)

[edit] Removal of "cite" tag for metallic polycrystals

Some one cited the fact that most metals encountered in daily life are polycrystalline. What the statement means is that metals have a grain structure. You can find this under the linked article for polycrystals, which the author was careful to link. The problem with this request for a cite is that the grain structure of metals is just about the first and most fundamental fact of metallurgy. It is like requesting a cite on the letter a if someone starts to recite the alphabet. All naturally occurring metals have a grain structure and you don't need a special note for that. True it needs to be mentioned somewhere but that is taken care of (with special note) under polycrystal. Thanks.Dave (talk) 12:43, 20 April 2008 (UTC)

[edit] Bob's Rock Shop

There is a link here to a site published by Bob's Rock Shop. I pondered whether this is to be considered primarily advertising. The owners however are genuine scientists using Bob's Rock Shop to publish scientific educational material under a separate heading. This is a tough call. Some advertising in this case is inadvertent. I decided to leave it in because the scientific material itself does not talk about Bob's Rock Shop. If this were a site from some university the university would be mentioned so in this case whether the publisher is profit or non-profit is only incidental. The topic is certainly open to discussion. Thanks.Dave (talk) 13:10, 20 April 2008 (UTC)

Similarly Krassmann's site contains links leading to a catalogue of his collection, which he will sell or trade. But, the scientific part is kept apart, so if I am leaving in Bob it seems fair to leave in Thomas. To separate advertising from source material is sometimes difficult and I think I have been pretty good about excising blatent sales material - the prices of papers, Amazon or other bookseller sites, porn sites who will sell you heaven knows what, authors peddling their books, businesses using their community's Wikipedia article, what have you. But if a scientist happens to use a private site to publish scientific material - well, it's on the line I think.Dave (talk) 14:45, 20 April 2008 (UTC)